1. Field of the Invention
The present invention relates to an image forming apparatus configured to be able to read an image of a document.
2. Description of the Related Art
Hitherto, there is known an image forming apparatus including an auto document feeder (ADF) capable of automatically feeding a document to an image reading portion capable of reading an image of the document in forming the image skimmed by the image reading portion on a sheet. Further, an image forming apparatus capable of forming images on both sides of a sheet normally includes a duplex conveying path configured to convey the sheet to an image forming portion to form the one image on a first surface of the sheet and then to reverse the sheet to convey the sheet again to the image forming portion to form the other image on a second surface of the sheet.
Here, the image forming apparatus including the ordinary automatic feeder poses a problem that the apparatus is enlarged because a document conveying path conveying a document and a sheet conveying path conveying a sheet are provided separately within the apparatus. Then, Japanese Patent Application Laid-open No. 2006-232467 has proposed an image forming apparatus downsized by commonizing a part of a document conveying path of the automatic feeder and a part of a duplex conveying path in a body of the image forming apparatus.
However, because the image forming apparatus described in Japanese Patent Application Laid-open No. 2006-232467 shares the duplex conveying path for feeding a document and for conveying a sheet, timings for conveying the sheet and the document are largely restricted in executing an image forming operation performed on the sheet and an image reading operation performed on the document. Therefore, the image forming apparatus described above has had a problem that productivity of the apparatus drops because it is difficult to carry out a copying function of reading an image from a document and of forming the read image on a sheet and to read an image of the document in forming an image.